Interlocking system for railroads



Patented Sept. 22, 1931 UNITED STATES PATENT OFFICE WIN'IHROP K. HOWE, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK INTERLOCKING SYSTEM FOR RAILROADS Application filed September 12,1929. Serial No. 392,139.

This invention relates to power interlocking sys'tems, and more particularly pertains to indicationmeans and devices for such sys-.

tems. v

In power interlocking systems employing the type of indication known as constant current or battery indication, the electro-responsive device, indicating in the tower the position and locked condition of the associated track switch, is usually controlled by point detector .contacts which are operated to an extreme posi ion when the'associated trackswitch is in a corresponding position and locked; and which are operated to a noncontacting intermediate position during the operation of the switch machine after said track switch is unlocked. In other words, there is a preliminary period of time during which the condition of the switch machine is changed from a normal static condition to an active unlocking condition preliminary to thecomplete unlocked condition. This preliminary period of time is not indicated in the tower by the elec ro-responsive device, which results in the possible completion of operations which are contrary tothe unlocked condition of the associated track switch.

In one type of indication system to which the present invention more particularly relates, the electro-responsive device, indicating the condition of the associated track switch, is employed for actuating an indicatio-n latch mechanism governing the movement of the control lever associated with the switch machine and track switch. 'In this type'of system, it may happen that an improper or false releasing of said indication latch mechanism may be accomplished under a certain combination of circumstances, due to the electro-responsive device'failing to anticipate the unlocked condition of the track switch. For example, when the operator moves a control lever to a new governing position, it he allows the switch machine :to receive power for a shortinterval of time, then immediately returns the lever to its former governing position during the period of time preceding the unlocking of the switch machine, the associated indication latch mechanism may be released, even though the op- Patent eration of the switch machine from its former n trol lever, or the like, the inertia of the motor armature and the gearing of the switch machine might unlock the switch points and even partially move them. This contingency would be unsafe, because the control lever would be in one extreme position, although the track switch would be unlocked and partly moved.

lVith these considerations in mind, the

present invention proposes to provide inter-.

locking systems with a constant current or battery type indication system having an electro-responsive device indicating in the tower the static condition of the controlling switch machine, as well as theposition and locked condition of the associated track switch. More specifically, the present invention provides contact means which is operably controlled by the initiation of the switch machine from its normal locked static condition, which contactmeans governs the indication of an electr c-responsive device located n the tower and associated therewith.

Various other ob]ects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawing and in part pointed out as the description of the invention progresses.

The single figure of the accompanying drawing represents in a diagrammatic manner one specific embodiment of the present invention, as applied to .one type of power operated switch machine; its associated track switch; its control lever; and other devices pertaining thereto.

With reference to the single figure of the drawing, a track switch TS is shown as operated by asuitable switch machine SM which is preferably of the type described in my No. 1,466,903 dated September 4,

'in the usual well known manner, such for example as explained in detail in my above referred to Patent N 0. 1,466,903. Likewise, the contacts indicated as included withiniadotted rectangle designated PCC are shown and described in detail in the above referred to Patent No. 1,466,903, and accomplish the reversability of stroke.

The contacts included within a dotted rectangle designated PD are known as point the switch machine in mid detector contacts and include a movable contact block 5 of insulating material which 13 caused to assume extreme normal and reverse posltions when the track switch TS is in corresponding positions and locked; but

it is caused to assume an intermediate position when the track switch is being operated "from one extreme position to another, or at any such time that said track switch 15 unlocked. Mounted upon the movable Contact block 5, there are contacts 6 and 7 which make contact between. their respective pairs of fixed contacts when in the normal or reverse extreme positions only. An example of an. operating mechanism for such point detector contacts isdisclosed in the patent to C. S. Bushn'elhPatent No. 1,517,236 dated N ovember 25, 1924;.

Associated with the pointdetector contacts PD, there is a local transformer T, the

primary of which is supplied with potential from a suitable alternating current source over a transmission line extending from the interlocking tower.

In the tower, a control lever L is provided which is capable of assuming the usual full normal and full reverse positions indicated by the arrows N and R respectively as they appear opposite the arrow A on the control lever L. These full positions of the lever L are supplemented by normal and reverse indicating positions designated by the arrows NI and RI respectively, which indicating positions are determined by an indicationlatch mechanism TM conventionally shown as including an indication magnet 10 and a plunger 11. The movement of the lever L 1 from a full position to an indication position,

operates a tappet bar 12 from a corresponding extreme position to a central position by means of a cam slot 13, for controlling the associated mechanical interlocking between levers in the usual well known manner.

The lever L also governs the operations of the switch machine SM over normal and reverse operating wires 14 and 15 respectively in conjunction with a common return wire C. The operating and indicating circuits are completed by movable contact members 16,17 and 18 which make contact between certain pairs of fixed contacts when the lever L is in the posit-ions N and N1, and make contact between certain other pairs of fixed contacts when the lever L is in the positions R and RI. A fuse 19 is included within the operating circuits as controlled by contacts 16 and 17.

Preferably, a suitable electric lever lock is employed with the lever L to prevent movement of said lever from its normal position N and reverse position R when the detector track section associated with the switch TS is occupied, however, such a lock has been omitted to simplify the description of the present invention.

An energysaving contact 20 is provided which may be actuated to a contacting position by the control of a lever latch 21.

Associated with the indication latch mechanism TM is a SS relay of the two phase alternating current-type, having a local phase winding and line phase winding 26. The local phase winding 25 is continuously energized from a secondary winding of a local transformer T which is connected to the same transmission line as the local transformer T at the switch machine SM. The line phase winding 26 is shown as controlled over 'two individual wires extending from the switch machine, however, it may be controlled in any other suitable manner, such for example, as disclosed in my pending application Ser. No. 392,138, filed September 12, 1929. This SS relay has a contact 27 which assumes either of two extreme positions depending upon therelative instantaneous polarity of the currents flowing in the local phase winding 25 and the line phase winding 26, and assumes a deenergized central positlon when either or both phase windings are deenergized.

Operably connected to the armature A of .the switch machine SM is a centrifugal governor GR which includes a contact 30 being normally biased, to make contact between two fixed contacts indicated as arrows, by a spring 31. The contact 30, however, is operated to a non-contacting position upon the initiation of rotation of the armature A by the centrifugal force of governor balls 32 and 33 in a manner that is obvious from the drawing. It is noted that the spring 1 shall be of sufiicient strength to cause the contact 30 to assume a contacting position only when the armature A is as rest, that is, it shall be strong enough to cause sufficient contact pressure. Also, the governor balls 32 and 33 shall be of sufficient weight to cause the contact 30 to assume a non-contacting position 'as soon as the armature A begins rotation,

such for example, as soon as the armature has made one-half revolution, or even less.

It'is believed that the usefulness and operation of such a system will be more readily understood by further description being given from the standpoint of the operation of the interlocking system taken as a whole.

Operation of the system In order to follow the coordination of the various devices of the interlocking system including a constant current type of indication system which indicates in the tower the position and locked condition of the associated track switch and also the static condition of the controlling switch machine it is deemed necessary to only consider the operation of the system from a normal condition to a reverse condition.

Vith the apparatus and circuits of the interlocking sysetm in the normal condition as shown, the contact 27 of the SS relay is in a right hand energized position, as the local winding 25 is continuously energized and the line-phase winding 26 is energized over a normal energizing circuit completed with the track switch TS and switch machine SM in a normal locked static condition.

The normal energizing circuit for the line phase winding 26 of the SS relay is traced as follows :from the right hand terminal of the secondary of transformer T, through wire 35, closed contact 30, wires 36 and 37, contacts 738, wires 39 and 40, line phase winding 26 of the SS relay, wires 41 and 42 contacts 6l4, wires 45 and 46, to the left hand terminal of the secondary of transformer T.

Let us assume that the operator desires to reverse the track switch TS, and to do so presses the lever latch 21 preparatory to moving the lever L in a left hand direction. This operation closes an energizing circuit through contact 20 for energizing the indication magnet 10, which circuit is traced as follows from the positive terminal of a suitable source of electric potential indicated as B+, through contact 27 in a right hand position, wire 48, contacts 1849, wires and 51, indication magnet 10, wire 52, closed contact 20, to the negative terminal of the suitable source of electrical potential indicated as Assuming the detector track section associated with the track switch TS to be unoccupied, then the associated lever look (not shown) will also be energized at this time, and the lever L may be moved, to the position RT. hen such movement is made, the circuit for the energization of the indication magnet 10 is opened at the contacts 18--4l9 as soon as the lever L leaves the position NI. Also, the plunger 11 is caused to assume a locking position by a projection 53, so that the lever L can not be moved beyond the position RI.

With the lever L in the reverse indication position RI, the reverseoperating circuit for the switch machine SM is completed by the movable contact 16 over the wire 15 in the usual manner well known to those skilled in the art. This operating circuit for the switch machine SM causes the motor armature A to rotate in a direction to cause the track switch to assume a reverse position in a manner set forth in my above mentioned Patent No. 1,466,903. As soon as the armature A initiates rotation, the contact 30 is operated to a non-contacting position which opens the energizing circuit of the line phase winding 26 of the SS relay. Thus, the contact 27 assumes a deenergized position.

As soon as the motor armature A has completed en ongh revolutions to unlock the track switch TS preparatory to its operation, the contacts 6 and 7 are caused to assume noncontacting positions with the Contact block in an intermediate non-contacting position.

Thus, it is seen that the circuit for energizing the line-phase winding 26 of the SS relay is further opened at contacts 6i l and 738.

lVhen the track switch TS has been operated'to the reverse position in the usual well known manner, it is locked and the movable contact block 5 is operated from an intermediate position to a reverse extreme position, in which position the circuit is closed for applying potential to the reverse energizingcircuit of the line phase winding 26 as soon as the motor art-nature A ceases to rotate and the contact 30 closes.

This reverse ener izing circuit for the line phase winding 26 or the SS rela is traced as follows:-from the right hand terminal of the secondary of transformer T, through wire 35, closed contact 30, wire 36, contacts 656, wires 57 and 41, line phase winding 26 of the SS relay, wires 40 and 58, contacts 759, wire 46, to the left hand terminal of the secondary of transformer T.

With the reverse energizing circuit for the line phase winding 26 of the SS relay completed, the contact 2? assumes a left hand dotted line position, so that the operator may press the lever latch 21, closing the contact 20 and thus energize the indication magnet 10. The energization of the indication magnet 10 operates the plunger 11 to an active position, that is, the indication latch mechanism IM releases the lever L in amanner to allow it to be moved to its full reverse position R.

Thus, one operation of the interlocking system embodying the present invention has been described, and it is obvious that the normal operation of the system, that is, the facility of operation, has not been hindered or retarded in any manner from completing its normal functions. However, the possibility of a false or improper indication, above mentioned as being present in the usual type of constant current or battery indication system, has been eliminated by the provision of an indication system giving a new fundamental indication in the interlocking tower, rather than compensating for the usual indication. The indication given by the system of the present invention is capable of anticipating the unlocked condition of its associated track switch, and does so by being responsive to the initial active conditionof the associated switch machine.

By way of further explanation, let us as sume that the free run of the switch machine motor, before the opening of the point detector contacts PD, is approximately thirteen and one half revolutions, as is the case in some instances. If then, in such a case, the governor contact 30 is opened during a fractional part of the first revolution, it is obvious that could the control lever L be returned to its former position in this short interval of time during the opening of contact 30, and reach its full position after releasing of the indication latch mechanism 1M, the switch would still be locked and in correspondence with its lever, because the motor armature would barely have enough momentum after removal of power to rotate it through a distance equal to that through which it had already passed. Thus, the motor would fall far short of un locking the associated track switch.

It is thought unnecessary to describe in detail the possible circumstances permitting an improper or false indication as heretofore mentioned. as the positive operation of the system has been. completely described and its safety and usefulness is comple vely obvious. However, such possible improper operation of the usual type of constant current or battery indication system has been explained in detail in my pending application Ser. No. 392.138, filed September 12. 1929.

It is obvious from the above description. that various means other than a contact operably controlled by a governor may be used according to the present invention. In other words, the static condition of a switch ma chine, or the fact that it is rest, may be indicated in various ways by controlling a contact from any suitable moving part of the switch machine in a manner such that its motion will be active to accomnlish the opening of said contact soon as the switch machine is initiated.

One specific construction of devices and arrangement of circuits, designed for use in connection with one particular type of indication system for use with interlocking systems, has been shown and described; however, it is to be understood that the various devices and circuit arrangements selected are to facilitate the disclosure and nature of the invention rather than its specific form, and it is to be further understood that various and indicating means giving indication in the tower of the position and locked condition of said track switch only if said switch machine is at rest.

2. In an interlocking system, a track switch operably controlled by a switch machine, a control lever located in a tower and governing the movement of said switch machine, point detector contacts controlled in accordance with the position and'loched condition of said track switch, contacting means automatically opened upon movement of said switch machine, a source of potential, and an electro-responsive device in the tower energized from said source of potential and controlled by said point detector contacts and said contacting means.

3. In an interlocking system, a track switch operated by a switch machine having a motor, a control lever located in a tower and governing the movement of said switch machine, point detector contacts operably controlled in accordance with the position and locked condition of said track switch. centrifugal contacting means automatically operated upon movement of said motor, a source of potential, and an electro-responsive device in the tower actively energized from said source of potential and controlled by said point detector contacts and said centrifugal contacting means.

4. In an interlocking system, a track switch controlled by a switch machine, a control lever located in a tower and governing the movement of said switch machine, point detector contacts controlled in accordance with the position and locked condition of said track switch, a contacting means, a fly-ball governor operably controlling said contacting means with said governor operated by said switch. machine, a source of potential, a three position relay in the tower energized to one of two ex reme positions by said source of potential in accordance with he positions assumed by said point detector contacts and said contacting means, whereby both the position and locked condition of said track switch and the static condition of said switch machine are indicated in the tower.

5. In an interlocking system, a track switch. a switch machine having a motor, a

control lever located in a tower and governins; said switch machine, a relay in the tower for indicating the condition of said track switch and having normal and reverse energizing circuits, point detector contacts for establishing either the normal or reverse energizing circuit of said relay and controlled in accordance with the condition of said track switch, and a governor contact operated by the motor of the switch machine for opening the circuits of said relay during operation of said switch machine.

6. In an interlocking system of the type shown and described, a control lever governing the movement of a switch machine, an indication latch mechanism associated with said control lever, a contacting means actuated to a non-contacting position when said switch machine is not at rest. and indication means including said contacting means capable of actuating said indication latch. mechanism when said control lever and said switch machine are in correspondence and said switch machine is at rest.

7 In an interlocking system for railroads, a control lever controlling a distant switch machine and releasing mechanical interlocking between levers, an indication latch mechanism for said control lever, and means for actuating said mechanism only if said switch machine is in correspondence with said control lever and is at rest.

8. In an interlocking system, a track switch, a switch machine, a control lever located in a tower and governing said switch machine, contacts controlled in accordance with the condition of said track switch, contacting means closed only if said switch machine is at rest, an electro-responsive device in the tower controlled by said contacts and said contacting means.

9. In an interlocking system, a track switch, a. switch machine, an electro-responsive means capable of giving a plurality of indications, contacts controlled by said track switch for causing said electro-responsive means to give a distinctive indication for each extreme locked position assumed by said track switch and a distinctive indication when said track switch is not locked, and contacting means controlled by said switch machine for causing said electro-responsive means to give indication that said track switch is unlocked whenever said switch machine is in operation.

10. In an interlocking system, a track switch, a switch machine, an electro-responsive device capable of giving a plurality of indications, contacts controlled by said track switch for causing said electro-responsive device to give a distinctive indication for each position of said track switch, and contacting means controlled by said switch machine for causing said elect-ro-responsive device to give a particular distinctive indication during the operation of said switch machine.

11. In an interlocking system, a track switch controlled by a switch machine, a control lever located in a tower and governing the movement of said switch machine, indication meansin the tower indicating the position and locked condition of said track switch, and means at the switch active, when the switch machine receives power, to cause said indication means to give an, indication cortracl'; switch is unlocked. 7

12. In combination, a switch machine for operating a railroad track switch having a motor, a contact operated when the motor is rotating above a predetermined speed, and indicating means controlled by said contact, and in accordance with the position of the track switch.

13. In combination, a switch machine for operating a railroad track switch, a contact normally biased to a closed position, means responsive to the motion of said switch machine tor opening said contact while said switch machine is operating, and electro-responsive means controlled in accordance with the closed or open position of said contact, and in accordance with the position of said switch machine.

14. In combination, a railroad track switch operating mechanism having a motor, a contact, a centrifuge operatively connected to said motor for opening and closing said con tact, a source of potential, an electro-responsive device, and circuits for said electro-responsive device from said source of potential controlled in accordance with the opened or closed condition of said contact, and in accordance with the position of said switch operating mechanism.

15. In combination, a track switch, a switch operating mechanism having a motor, a centrifugal device operatively connected to said motor, a contact normally biased to a closed position opened by said device when said motor is in operation, an indicating relay distinctively controlled when energized with one polarity or another or when deenergized, pole changing means operatively connected to said track switch, a source of en- ,70 responding to the indication given when said ergy, and polarized energizing circuits for said indicating relay including said pole changing means, said contact and said source of energy, whereby said indicating relay is distinctively controlled in accordance with the position of said track switch and the operation of said motor.

16. In combination, a switch machine having a motor, pole changing contacts operated to normal or reverse positions in accordance with the position of said switch machine, a centrifugally controlled contact operatively connected to said motor, an electro-responsive device for governing traffic controlling means, a source of energy, and energizing circuits for said electro-responsive device including said pole changing contacts, said centrifugally controlled contact, and said source of energy.

17. In an interlocking system, a track switch, a switch machine for operating said track switch, a control lever for governing said switch'machine, an indication latch preventing movement of said control lever from an intermediate position to a corresponding extreme position except when actuated, pole changing contacts operated by said track switch, a centrifuge connected to said switch machine, a contacting means operated by said centrifuge, a three position polar relay, energizing circuits for said relay having the polarity applied thereto determined'by said pole changing contacts and the energization thereof dependent upon said contacting means, and means for actuating said indication latch when said relay is in correspondence with said control lever.

18. In combination, a switch machine for 7 operating a railroad track switch, one contact means normally biased to a closed position, means responsive to the motion of said switch machine for opening said one contact means only While said switch machine is operating, another contact means operated in accordance with the extreme position of said switch machine, and electro-responsive means controlled in accordance with said one and said another contact means.

In testimony whereof I aifix my signature.

WINTHROP K. HOWE. 

